Dynamic prediction of demand cycles for temperature overshoot control in a thermostat

Abstract

A heating, ventilation, and air conditioning (HVAC) control device comprises a network interface and a processor operably coupled to one another. The processor is configured to trigger a demand cycle in which an HVAC system, collect event data for the demand cycle from one or more devices, electronically calculate, over the demand cycle, a temperature error between the set point temperature and the sensed temperature, determine a predicted temperature error at an expected end time of the demand cycle, associate a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle, associate an additional point in time where a rate of change of the temperature error is determined to meet a threshold with a corrected end time of the demand cycle, assign an expected time duration for an additional demand cycle, and trigger the additional demand cycle.

Description

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 763,863, filed Feb. 26, 2025, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to thermostat control for a heating, ventilation, and air conditioning (HVAC) system, and more specifically to a thermostat performing predictive demand termination for temperature overshoot control.BACKGROUND

[0003] A heating, ventilation, and air conditioning (HVAC) system may be utilized generally to regulate temperature within an enclosed space. Specifically, air is cooled via heat transfer with refrigerant flowing through the HVAC system and returned to the enclosed space as conditioned air. While some enclosed spaces may include multiple HVAC systems, temperatures may nevertheless vary across enclosed spaces depending on the physical dimensions and the architecture of the enclosed spaces. Further, temperatures may vary across enclosed spaces depending on a thermostat's ability to accurately set temperature set points within the enclosed spaces.SUMMARY

[0004] In one or more embodiments, a system and method described herein are configured to perform predictive demand termination for temperature overshoot control in a thermostat. In particular, the system may be configured to account for changes in the load of a heating, ventilation, and air conditioning (HVAC) system. The load may be changed by modifying a set point temperature in a space (e.g., an enclosed space). Herein, the system is configured to inhibit and / or eliminate temperature overshoots for an HVAC demand cycle under light system loads. The system may be configured to dynamically adjust an expected duration of demand cycles in the HVAC system to inhibit and / or eliminate overshoots when controlling a temperature of the space. At the moment of controlling the HVAC system to change the temperature in the space, a thermostat may be configured to compensate for any changes in HVAC loads. Herein, the system is configured to accurately set an actual temperature in a space without being affected by changes in the HVAC loads.

[0005] In some embodiments, the system provides technical solutions for technical problems. In this regard, the system is configured to accurately set a temperature in a space while the HVAC system transitions from one state to another state. The states may comprise operations in which resource consumption at the thermostat is modified. For example, an “idle” state for the thermostat may be a period of time in which the thermostat is in low-power consumption as a temperature inside the space is allowed to fluctuate freely and / or within a range. In another example, an “active” state for the thermostat may be a period of time in which the thermostat is required to consume large amounts of its memory resources and processing resources to control an HVAC system to modify the temperature and / or humidity in a space.

[0006] In conventional systems, as the HVAC system transitions between states, the temperature in the space may be incorrectly modified due to improper accounting of an HVAC load. Incorrect sampling coupled with incorrect accounting of the HVAC loads leads to incorrect temperature and / or humidity regulation in the space. The lack of reliable temperature and / or humidity regulation may cause irreparable losses to users, infrastructure, and / or operations in the space. For example, an inaccurate temperature control in a space comprising a datacenter may cause servers to overheat. Overheating servers may lead to various issues including data loss, system malfunctions, performance degradation, and potential damage to physical components of the server.

[0007] In one or more embodiments, contrary to conventional systems, the system disclosed herein is configured to monitor error functions associated with a difference between a sensed temperature and a set point temperature over a demand cycle. As the demand cycle concludes, the system may be configured to determine an overshoot of the demand cycle and analyze the overshoot to predict a future demand cycle. In this regard, the system may be configured to control future demand cycles to account for information associated with previously sampled overshoots.

[0008] In one or more embodiments, the systems may comprise an apparatus, such as an HVAC control device. Further, the device may be a data exchange system, which comprises the apparatus. In addition, the device may be configured to perform operations as part of a process performed by the apparatus. As a non-limiting example, the apparatus may comprise a network interface configured to communicate with one or more devices, a memory, and a processor communicatively coupled to one another. The processor may be configured to trigger a demand cycle in which an HVAC system is configured to match a sensed temperature in a space to a set point temperature and collect event data for the demand cycle from one or more devices. The event data may comprise a timestamp indicating a start time of the demand cycle, a set point temperature value for the HVAC system, and a sensed temperature value of the space.

[0009] Further, the processor may be configured to electronically calculate, over the demand cycle, a temperature error between the set point temperature and the sensed temperature, electronically extract a rate of change value of the temperature error over a first portion of the demand cycle, determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error at an expected end time of the demand cycle; and monitor the temperature error over a second portion of the demand cycle.

[0010] In conjunction with monitoring the temperature error over the second portion of the demand cycle, the processor may be configured to determine whether the temperature error matches the predicted temperature error. Further, the processor may be configured to associate a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle in response to determining that the temperature error matches the predicted temperature error and monitor the rate of change of the temperature error over a period of time that is subsequent to the demand cycle.

[0011] In conjunction with monitoring the rate of change of the temperature error over the period of time, the processor may be configured to determine whether the rate of change of the temperature error is equal to a limit value (e.g., preset value, such as zero). Further, the processor may be configured to associate an additional point in time where the rate of change of the temperature error is determined to be equal to the limit value with a corrected end time of the demand cycle in response to determining that the rate of change of the temperature error is equal to the limit value, assign, based on the start time and the corrected end time, an expected time duration for an additional demand cycle, and trigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature over the expected time duration.

[0012] Certain embodiments of the present disclosure may include some, all, or none of these advantages. These advantages and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0014] FIG. 1 is a schematic diagram of heating, ventilation, and air conditioning (HVAC) control system in accordance with one or more embodiments;

[0015] FIGS. 2A and 2B illustrate dynamic control of demand cycles as performed by the system of FIG. 1 in accordance with one or more embodiments;

[0016] FIG. 3 is an operational flow comprising predictive demand termination for temperature overshoot control performed by the system of FIG. 1 in accordance with one or more embodiments;

[0017] FIGS. 4A and 4B are a flowchart of an embodiment of a thermostat predictive demand termination method performed by the system of FIG. 1 in accordance with one or more embodiments;

[0018] FIG. 5 is a schematic diagram of an embodiment of a device configured to control an HVAC system in accordance with one or more embodiments; and

[0019] FIG. 6 is a schematic diagram of an embodiment of an HVAC system in accordance with one or more embodiments.DETAILED DESCRIPTION

[0020] As described above, this disclosure provides various systems and methods to perform predictive demand termination for temperature overshoot control.Information System Overview

[0021] FIG. 1 is a schematic diagram of heating, ventilation, and air conditioning (HVAC) control system 100 that is configured to perform multi-state predictive temperature compensation operations. In one embodiment, the HVAC control system 100 comprises a controller 102, an HVAC system 104, a thermostat 106, and devices 108 that are in signal communication with each other in a network 124.

[0022] The network 124 may be any suitable type of wireless and / or wired network including, but not limited to, all or a portion of the Internet, an Intranet, a private network, a public network, a peer-to-peer network, the public switched telephone network, a cellular network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), and a satellite network. The network 124 may be configured to support any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.

[0023] The HVAC system 104 is generally configured to control the temperature of a space 122. Examples of a space 122 include, but are not limited to, a room, a home, an office, or a building. The HVAC system 104 may comprise a thermostat 106, compressors, blowers, evaporators, condensers, and / or any other suitable type of hardware for controlling the temperature of the space 122 as would be appreciated by one of ordinary skill in the art. An example of an HVAC system 104 configuration and its components is described below in FIG. 6. The HVAC system 104 comprises one or more thermostats 106 located within the space 122. A thermostat 106 may be a single-stage thermostat, a multi-stage thermostat, or any suitable type of thermostat as would be appreciated by one of ordinary skill in the art. The thermostat 106 is configured to allow a user to select a desired temperature or set point temperature for the space 122. The controller 102 may use information from the thermostat 106 such as the set point temperature for controlling a compressor and / or a blower. In one embodiment, the thermostat 106 and the controller 102 are integrated into a single device. In another embodiment, the thermostat 106 may be a device that is external from the controller 102. In this example, the thermostat 106 is in signal communication with the controller 102 using any suitable type of wired or wireless communications.

[0024] The controller 102 is further configured to perform multi-state predictive temperature compensation. In some embodiments, contrary to conventional systems, the controller 102 is configured to accurately compensate for internal heat rise in the thermostat 106, where a single compensation value is not sufficient to cover multiple states. For example, the controller 102 may be configured to evaluate multiple collected temperature values from inside the thermostat 106 in accordance with specific state conditions to obtain one or more compensation values. The controller 102 is configured to provide a sensed temperature value in a space using an overall compensation value. The overall compensation value is electronically calculated by dynamically weighting different compensation values at different rates. The controller 102 may use the sensed temperature to trigger operations in an HVAC system to adjust a temperature more precisely in the space.

[0025] The controller 102 may be configured to control the operation of the HVAC system 104 using artificial intelligence (AI). In one embodiment, the controller 102 is configured to collect event data 114 from one or more devices 108 to generate an artificial intelligence model 112 for predicting an occupancy schedule and / or a set point temperature schedule for the space 122. Examples of devices 108 include, but are not limited to, computers, mobile devices (e.g., smart phones or tablets), user devices, Internet-of-things (IoT) devices, home automation devices, AI devices, motion sensors, proximity sensors, or any other suitable type of device. An event is an action that is taken by a user that provides information to the controller 102 about a user's behavior or preferences. The event data 114 may comprise a timestamp 116 indicating a time when an event occurred, an occupancy status 118 (e.g., a present status or an away status) for a user, a set point temperature 120, a source identifier that identifies a data source (e.g., a device identifier), a user identifier, a space identifier, or any other suitable type of information.Sample Embodiments

[0026] FIGS. 2A and 2B illustrate a sample 200a and a sample 200b, respectively, in which the system 100 of FIG. 1 is configured to perform dynamic prediction of demand cycles for temperature overshoot control in a thermostat 106, in accordance with one or more embodiments. The sample 200a and the sample 200b may be embodiments showing a load change in the HVAC system 104 over time. The sample 200a and the sample 200b may be generated after performing one or more operations by the controller 102, the HVAC system 104, the thermostat 106, and / or one or more devices 108. In FIGS. 2A and 2B, demand cycles are shown in comparison with a load consumption over time. The samples 200a-200b show the demand cycle as defined by values of temperature error Terror and time. The temperature error Terror may be a difference between a set point temperature and a sensed temperature. The sensed temperature may be referred to as HSP for heating sensed temperature Tsensed and CSP for cooling sensed temperature Tsensed.

[0027] In FIG. 2A, the sample 200a shows a demand curve changing vertically with reference to an axis 202 and changing horizontally with reference to an axis 204. The sample 200a shows a demand cycle 210 in which the HVAC system 104 is configured to account for a new load value. The demand cycle 210 may comprise a portion 212 and a portion 214. The portion 212 and the portion 214 may correspond to specific behavior of the demand curve. For example, the portion 212 may correspond to a prior portion of the demand cycle 210 and the portion 214 may correspond to an active portion of the demand cycle 210. The HVAC system 104 may be active throughout the demand cycle 210 and possibly after. Herein, the demand cycle 210 may be representative that the thermostat 106 is actively (e.g., currently) asking the HVAC system 104 for output. For example, individual controllers in the HVAC system 104 (e.g., in an indoor unit) may be kept running after the thermostat 106 ends demand (e.g., to exhaust a heat built up in a heat exchanger or coil). A reason for a continued increase in temperature error after the start of a demand cycle 210 may be that the HVAC system 104 has some inertia because the HVAC system 104 may take time to effect change in temperature, and there may be effects of duct temperature on a conditioned space. In the example of FIG. 2A, the demand cycle 210 changes from a point in time 220 (e.g., a time point) and a point in time 222. The demand cycle 210 may last from the point in time 220 where the temperature error Terror is less than an ON-demand temperature to the point in time 222 where the temperature error Terror is greater than an OFF-demand temperature. A difference between the point in time 220 and the point in time 222 may be a period of time. At a point in time 224, the demand curve may change from a rising behavior to a falling behavior as exemplified by point 226.

[0028] In some embodiments, a difference in time from a point in time 220 to the point in time 224 may last a duration 230. The duration 230 may comprise a duration 232 and a duration 234. The duration 232 may comprise a fall in the demand curve after the demand cycle is started. The duration 234 may comprise a raise in the demand curve after the demand cycle reaches a lower point (in comparison to the rest of the demand curve) and / or the lowest point in the demand curve and until the demand curve reaches a higher point (in comparison to the rest of the demand curve) and / or the highest point in the demand curve.

[0029] In one or more embodiments, a difference in the temperature error Terror from an error value where the demand cycle ends to the highest point in the demand curve is considered an overshoot 240 of the demand cycle. In some embodiments, the overshoot 240 shows a response of the HVAC system 104 where a sudden input change (e.g., in the load change of the HVAC system 104) exceeds an intended output level. In FIG. 2A, the demand cycle 210 does not meet the duration 230.

[0030] In FIG. 2B, the sample 200b shows a demand curve changing vertically with reference to an axis 252 and changing horizontally with reference to an axis 254. The sample 200b shows a demand cycle 260 in which the HVAC system 104 is configured to account for a new load value. The demand cycle 260 may comprise a portion 262 and a portion 264. The portion 262 and the portion 264 may correspond to specific behavior of the demand curve. For example, the portion 262 may correspond to a prior portion of the demand cycle 260 and the portion 264 may correspond to an active portion of the demand cycle 260. In the example of FIG. 2B, the demand cycle 260 changes from a point in time 270 (e.g., a time point) and a point in time 272. The demand cycle 260 may last from the point in time 270 where the temperature error Terror is less than an ON-demand temperature to the point in time 272 where the temperature error Terror is greater than an OFF-demand temperature. A difference between the point in time 270 and the point in time 272 may be a period of time. At a point in time 274, the demand curve may change from a rising behavior to a falling behavior as exemplified by point 276.

[0031] In some embodiments, a difference in time from a point in time 270 to the point in time 272 may last a duration 280. The duration 280 may comprise a duration 282 and a duration 284. The duration 282 may comprise a fall in the demand curve after the demand cycle is started. The duration 284 may comprise a raise in the demand curve after the demand cycle reaches a lower point (in comparison to the rest of the demand curve) and / or the lowest point in the demand curve and until the demand curve reaches a higher point (in comparison to the rest of the demand curve) and / or the highest point in the demand curve.

[0032] In one or more embodiments, a difference in the temperature error Terror from an error value where the demand cycle ends to the highest point in the demand curve is considered an overshoot 290 of the demand cycle. In some embodiments, the overshoot 290 shows a response of the HVAC system 104 where a sudden input change (e.g., in the load change of the HVAC system 104) exceeds an intended output level. In FIG. 2B, the demand cycle 260 meets most of the duration 280 by being active.

[0033] In one or more embodiments, the sample 200a may be a first demand curve in which an HVAC system 104 runs a demand cycle 210 for a first load. During the entirety of the sample 200a, An HVAC control device may be configured to monitor and analyze changes in the demand curve, analyze information associated with one or more points in the demand curve, and use results from the analyses to generate one or more commands to control future demand cycles. For example, the analyses of the demand cycle 210 in the sample 200a may be used to dynamically control the demand cycle 260 in the sample 200b. Herein, the sample 200a and the sample 200b may be subsequent load control samples in which the HVAC system 104 dynamically compensates load control from the sample 200a to the sample 200b.

[0034] In one or more embodiments, when controlling temperature in a conditioned space (e.g., an embodiment of the space 122) using staged control operations, the controller 102 and / or the thermostat 106 may be configured to calculate a temperature error Terror between a temperature setpoint Tsetpoint and a sensed temperature Tsensed. The temperature error Terror may be represented in the following embodiment:Te⁢r⁢r⁢o⁢r=Ts⁢e⁢n⁢s⁢e⁢d-Ts⁢etpoint

[0035] The controller 102 and / or the thermostat 106 may be configured to monitor the temperature error as a reference parameter to control load demands for heating and cooling in the HVAC system 104. The controller 102 and / or the thermostat 106 may call for a demand cycle when the temperature error Terror drops below a threshold relative to the set point temperature and stop the demand cycle when the temperature error Terror rises above another threshold above the set point temperature. The HVAC system 104 may comprise a blower-off delay to extract additional energy from the demand cycle. If system capacity is large compared to a load on the HVAC system 104, when the demand is ended, a temperature may keep rising above a set point temperature. The additional raise above the set point temperature may create an overshoot (e.g., the overshoot 240 in FIG. 2A and the overshoot 290 in FIG. 2B) relative to the targeted temperature in the conditioned space. In some instances, larger overshoots may lead to an experienced inaccuracy of the control of the temperature to the selected set point temperature by controller 102 and / or the thermostat 106.

[0036] In one or more embodiments, the HVAC control device may be configured to reduce, inhibit, and / or eliminate the overshoot. The HVAC control device may be configured to monitor a slope of the temperature error Terror during an active portion of the demand cycle, use the monitored slope to electronically calculate a predicted error for a set period tprediction into the future, and ending the demand cycle when an upper threshold is met based on a predicted error at a predicted ending time. Further, the HVAC control device may be configured to monitor the slope of the temperature error Terror after completion of the demand cycle to determine an amount of time in which the temperature keeps rising and capturing the amount of time as additional time configured to inform a new value for tprediction in a subsequent demand cycle.

[0037] In some embodiments, the HVAC control device creates an adaptive loop where changes in the demand cycle control the temperature error Terror positively or negatively. A change in the temperature error Terror may represent additional heating / cooling after an end of a demand cycle. Herein, the change is captured in an updated value of the set period tprediction and accounted for in a subsequent (e.g., next) demand cycle, limiting, inhibiting, and / or removing the overshoot. Limiting, inhibiting, and / or removing the amount of positive or negative adjustment of the set period tprediction per cycle may be configured to control min / max set time tprediction, and minimum actual temperature error Terror to let the predicted temperature error Terror take effect.Operational Flow

[0038] FIG. 3 shows an operational flow 300 in which the system 100 of FIG. 1 is configured to perform dynamic predictions of demand cycles for temperature overshoot control in a thermostat 106, in accordance with one or more embodiments. The operational flow 300 may be performed by the controller 102, the HVAC system 104, the thermostat 106, and / or one or more devices 108. In FIG. 3, the operational flow 300 comprises multiple operations performed by one or more elements, electronic components, and / or devices. In FIG. 3, the one or more elements, electronic components, and / or devices may comprise a slope calculator 302, a temperature error calculator 304, a temperature error predictor 306, and a demand control 308. The one or more elements, electronic components, and / or devices may be configured to receive inputs 310-320 and generate and / or create outputs 342-350.

[0039] In one or more embodiments, the inputs 310-316 may comprise temperature samples at different points in time. In some embodiments, the input 316 may be a first temperature value Tn-0, the input 314 may be a second temperature value Tn-1 that is prior to the first temperature value Tn-0, the input 312 may be a third temperature value Tn-2 that is prior to the second temperature value Tn-1, and the input 310 may be a fourth temperature value Tn-3 that is prior to the third temperature value Tn-2. The first temperature value Tn-0 may be a current temperature value. The inputs 310-316 may be provided to the slope calculator 302, which may sample the temperature values over a time duration. In some embodiments, the slope calculator 302 may be configured to generate the output 342 comprising a slope value. The slope value may be a rate of change of the temperature collected in the inputs 310-316 over a period of time. The measurement units associated with the rate of change may be a temperature measurement value over a time measurement value. For example, the rate of change may be degrees in Fahrenheit (F) or Celsius (C) over time in seconds(s).

[0040] In one or more embodiments, the input 318 and the input 320 may comprise temperature samples at different points in time. In some embodiments, the input 318 may be the first temperature value Tn-0 and the input 320 may be a set point temperature value Tsp. The input 318 and the input 320 may be provided to the temperature error calculator 304, which may electronically calculate a difference between the sampled temperature value Tn-0 and the set point temperature value Tsp. The first temperature value Tn-0 may be a current temperature value. In some embodiments, the temperature error calculator 304 may be configured to generate the output 344 comprising the temperature error Terror (or Terr). The measurement unit for the temperature error Terror may be a temperature measurement value. For example, the temperature measurement value may be degrees in Fahrenheit (° F.) or Celsius (° C.).

[0041] In one or more embodiments, the temperature error predictor 306 may be configured to receive multiple inputs 332 and generate an output 346 and an output 348. The temperature error predictor 306 may be configured to receive the output 342 and the output 344 as inputs. In some embodiments, the temperature error predictor 306 may be configured to predict a future error temperature value at a given time. In some embodiments, the temperature error predictor 306 may be configured to generate the output 346 comprising a prediction set time tprediction. The measurement unit of the set time may be a time measurement value. For example, the time measurement value may be in seconds(s). Further, the temperature error predictor 306 may be configured to generate the output 348 comprising the temperature error Terror and a predicted temperature error Terr-predicted′ which is an expected temperature error the temperature error Terror at the end of the prediction set time tprediction. The measurement unit of the predicted temperature error Terr-predicted may be a temperature measurement value. For example, the temperature measurement value may be degrees in Fahrenheit (F) or Celsius (° C.).

[0042] In some embodiments, demand control 308 may be configured to generate a demand output 350 that may be applied to temperature error predictor 306 to refine the temperature error and predicted temperature error of output 348. The demand control 308 may be configured to generate output 350 based at least in part upon the output 348. The demand control 308 may be configured to generate the output 350 comprising a demand value, which is signaling configured to cause a change in the temperature of the space 122. The demand value may be provided to the HVAC system 104, which is configured to modify flow of air at a magnitude proportionate to the demand value. The measurement unit of the demand value may be a temperature value. For example, the temperature value may be degrees in Fahrenheit (F) or Celsius (° C.).

[0043] In one or more embodiments, the inputs 332 may comprise one or more initial values in the HVAC system 104. These initial values may be a time set prediction default time tprediction-default, a maximum time set prediction time boundary tprediction-max, a minimum time set prediction time boundary tprediction-min, and a time set prediction step tprediction-step, which are used as a reference from which to calculate the prediction set time tprediction. The time set prediction default time tprediction-default may be a default time used when no prior information is available to modify the prediction set time tprediction. The time set prediction default time tprediction-default may be representative of a duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating an average duration for a specific load. The maximum time set prediction time boundary tprediction-max may be a limit to which the value of the prediction set time tprediction may be adjusted. The maximum time set prediction time boundary tprediction-max may be a maximum duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating a maximum expected duration for a specific load. The minimum time set prediction time boundary tprediction-min may be a limit to which the value of the prediction set time tprediction may be adjusted (e.g., zero). The minimum time set prediction time boundary tprediction-min may be a minimum duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating a minimum expected duration for a specific load. The time set prediction step tprediction-step may be a default step increase of a duration for the prediction set time tprediction. The measurement units of the a time set prediction default time tprediction-default, the maximum time set prediction time boundary tprediction-max, the minimum time set prediction time boundary tprediction-min, and the time set prediction step tprediction-step may be time measurement values. For example, the time measurement value may be in seconds(s). The rate of change in the demand cycle may be contained at a specific limit slope value limit slope. The specific limit slope value limitslope may be a value of a calculated slope where at which the temperature error Terror is no longer considered rising after a termination of the demand. In this regard, a limit used to determine an adjustment of prediction set time tprediction after demand is completed. The measurement units associated with the specific limit slope value limitslope may be a temperature measurement value over a time measurement value. For example, the rate of change may be degrees in Fahrenheit (° F.) or Celsius (C) over time in seconds(s).

[0044] In one or more embodiments, during an active portion of a demand cycle, the HVAC control device may be configured to monitor a calculated slope (e.g., an absolute value), electronically calculate the temperature error Terror relative to the setpoint temperature, and electronically calculate the predicted temperature error Terr-predicted at the end of the prediction set time tprediction for a future demand cycle based on rates of change in demand curves. If the predicted temperature error Terr-predicted is less than a predetermined threshold, the demand cycle may be ended. If the predicted temperature error Terr-predicted is greater than or equal to a predetermined threshold, the demand cycle may be ended. Herein, the temperature error Terror may be used for staging and as boundary for shut off. Further, the temperature error Terror and predicted temperature error Terr-predicted may become positive when the HVAC system 104 has met a set point temperature and demand ends when reaching a set positive limit.

[0045] In one or more embodiments, as the demand cycle transitions from the active portion of the demand cycle to a no demand portion, the HVAC control device may be configured to capture a time of demand state change and monitor an electronic calculated slope (e.g., an absolute value). Herein, as long as the rate of change value of the temperature error Terror over time during the demand cycle is greater than the specific limit slope value limitslope (e.g., slope≥limitslope), the HVAC control device may continue monitoring the rate of change value of the temperature error Terror over time. In some embodiments, when the rate of change value of the temperature error Terror over time during the demand cycle is less than or equal to the specific limit slope value limitslope (e.g., slope≤limitslope), latch the prediction set time tprediction as a delta to time of demand state change and limit checks against the minimum time set prediction time boundary tprediction-min and the maximum time set prediction time boundary tprediction-max for subsequent demand cycles.Example Process

[0046] FIGS. 4A and 4B are a flowchart of an embodiment of a dynamic prediction process 400 for an HVAC system 104, in accordance with one or more embodiments. Modifications, additions, or omissions may be made to the process 400. The process 400 may comprise more, fewer, or other operations than those shown in FIGS. 4A and 4B. For example, operations may be performed in parallel or in any suitable order. While at times discussed as the controller 102, the HVAC system 104, the thermostat 106, one or more devices 108, and / or components of any of thereof performing operations described in operations 402-458 in the process 400, any suitable system or components of the system 100 may perform one or more operations of the process 400. For example, one or more operations of the process 400 may be implemented, at least in part, in the form of instructions, stored on non-transitory, tangible, machine-readable media (e.g., a non-transitory computer-readable medium such as memory 504 of FIG. 5) that when run by one or more processors (e.g., the processor 502 of FIG. 5) may cause the one or more processors to perform operations described in operations 402-458.

[0047] The process 400 starts at operation 402, where an HVAC control device is configured to trigger a demand cycle in which an HVAC system 104 is configured to match a sensed temperature Tsensed in a space 122 to a set point temperature Tsetpoint. At operation 404, the HVAC control device is configured to collect event data 114 for the demand cycle from one or more devices 108. The event data 114 may comprise a timestamp 116 indicating a start time of the demand cycle, a set point temperature value for the HVAC system 104, and a sensed temperature value of the space 122. At operation 406, the HVAC control device is configured to electronically calculate, over the demand cycle, a temperature error Terror between the set point temperature Tsetpoint and the sensed temperature Tsensed. At operation 408, the HVAC control device is configured to electronically extract a rate of change value of the temperature error Terror over a first portion of the demand cycle. At operation 410, the HVAC control device is configured to determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error Terror-predicted at an expected end time of the demand cycle. At operation 412, the HVAC control device is configured to monitor the temperature error Terror over a second portion of the demand cycle.

[0048] At operation 420, the HVAC control device is configured to determine whether a temperature error Terror matches a previously predicted temperature error Terr-predicted for a current demand. In some embodiments, when a demand starts, a temperature error Terror along with the slope of the a temperature error Terror and the prediction set time tprediction is used to determine the predicted temperature error Terr-predicted. Herein, the predicted temperature error Terr-predicted may be used to determine when to end the demand. Once demand is ended, the slope of the temperature error Terror and time since demand ended is used to determine a modified prediction set time tprediction for a next cycle.

[0049] If the HVAC control device determines that the temperature error Terror does not match the predicted temperature error Terror-predicted (e.g., NO), the process 400 proceeds to operation 422. At operation 422, the HVAC control device is configured to determine that the temperature error Terror does not match the predicted temperature error Terror-predicted. If the HVAC control device determines that the temperature error Terror matches the predicted temperature error Terror-predicted (e.g., YES), the process 400 proceeds to operation 432. At operation 432, the HVAC control device is configured to determine that the temperature error Terror matches the predicted temperature error Terror-predicted. At operation 434, the HVAC control device is configured to associate a point in time where the temperature error Terror is determined to match the predicted temperature error Terror-predicted with an end time of the demand cycle. At operation 436, the HVAC control device is configured to monitor the rate of change of the temperature error Terror over a period of time that is subsequent to the demand cycle.

[0050] The process 400 continues at operation 440, where the HVAC control device is configured to determine whether a rate of change of the temperature error Terror over time is greater than or equal to a threshold value (e.g., the limit slope value limit slope). Herein, the threshold value may be equal to a limit value (e.g., preset value, such as zero). If the HVAC control device determines that the rate of change is not greater than or equal to the threshold value (e.g., NO), the process 400 proceeds to operation 442. At operation 442, the HVAC control device is configured to determine that the rate of change of the temperature error Terror does not meet the threshold value. If the HVAC control device determines that the rate of change is greater than or equal to the threshold value (e.g., YES), the process 400 proceeds to operation 452. At operation 452, the HVAC control device is configured to determine that the rate of change of the temperature error Terror meets the threshold value. At operation 454, the HVAC control device is configured to associate an additional point in time where the rate of change of the temperature error Terror is determined to be equal to match the threshold with a corrected end time of the demand cycle. At operation 456, the HVAC control device is configured to assign, based on the start time and the corrected end time, an expected time duration Tsetpoint for an additional demand cycle.

[0051] The process 400 may end at operation 458, where the HVAC control device is configured to trigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature Tsetpoint over the expected time duration Tsetpoint.

[0052] In one or more embodiments, the HVAC control device may be configured to dynamically inhibit and / or eliminate overshoots in demand cycles under light system loads. In some embodiments, a difference between demand overshoots of two demand curves may be a positive adjustment value. Further, difference between demand overshoots of two demand curves may be a negative adjustment value. The demand cycle may be triggered by an interaction between a user and an adjustment in a set point interface. The demand cycle may be triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by at least one of the one or more devices 108. The demand cycle may be triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by the HVAC system 104.Controller Hardware Configuration

[0053] FIG. 5 is an embodiment of a device (e.g., controller 102) configured to control an HVAC system 104. The controller 102 comprises a processor 502, a memory 504, and a network interface 506. The controller 102 may be configured as shown or in any other suitable configuration.

[0054] The processor 502 may comprises one or more processors operably coupled to the memory 504. The processor 502 may be any electronic circuitry including, but not limited to, state machines, one or more central processing unit (CPU) chips, logic units, cores (e.g., a multi-core processor), field-programmable gate array (FPGAs), application specific integrated circuits (ASICs), or digital signal processors (DSPs). The processor 502 may be a programmable logic device, a microcontroller, a microprocessor, or any suitable combination of the preceding. The processor 502 may be communicatively coupled to and in signal communication with the memory 504. The one or more processors may be configured to process data and may be implemented in hardware or software. For example, the processor 502 may be 8-bit, 16-bit, 32-bit, 64-bit or of any other suitable architecture. The processor 502 may include an arithmetic logic unit (ALU) for performing arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and executes them by directing the coordinated operations of the ALU, registers and other components.

[0055] The one or more processors may be configured to implement various instructions. For example, the one or more processors may be configured to execute instructions to implement an HVAC control engine 508. In this way, processor 502 may be a special purpose computer designed to implement the functions disclosed herein. In an embodiment, the HVAC control engine 508 may be implemented using logic units, FPGAs, ASICs, DSPs, or any other suitable hardware. The HVAC control engine 508 may be configured to operate as described in FIGS. 1-4B. For example, the HVAC control engine 508 may be configured to perform the operations of process 400 as described in FIGS. 4A and 4B.

[0056] The memory 504 may comprise one or more disks, tape drives, or solid-state drives, and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution. The memory 504 may be volatile or non-volatile and may comprise read-only memory (ROM), random-access memory (RAM), ternary content-addressable memory (TCAM), dynamic random-access memory (DRAM), and static random-access memory (SRAM).

[0057] The memory 504 may be operable to store HVAC control instructions 510, event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514, and / or any other data or instructions. The HVAC control instructions 510 may comprise any suitable set of instructions, logic, rules, or code operable to execute the HVAC control engine 508. The event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514 may be configured similar to the event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514 described in FIGS. 1-4.

[0058] The network interface 506 may be configured to enable wired and / or wireless communications. The network interface 506 may be configured to communicate data between the controller 102 and other devices (e.g., HVAC system 104, thermostat 106, and devices 108), systems, or domain. For example, the network interface 506 may comprise a WIFI interface, a LAN interface, a WAN interface, a modem, a switch, or a router. The processor 502 may be configured to send and receive data using the network interface 506. The network interface 506 may be configured to use any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.HVAC System Configuration

[0059] FIG. 6 is a schematic diagram of an embodiment of an HVAC system 104. The HVAC system 104 may condition air for delivery to an interior space of a building. In some embodiments, the HVAC system 104 is a rooftop unit (RTU) that is positioned on the roof of a building and the conditioned air is delivered to the interior of the building. In other embodiments, portions of the system may be located within the building and a portion outside the building. The HVAC system 104 may also include heating elements that are not shown here for convenience and clarity. The HVAC system 104 may be configured as shown in FIG. 6 or in any other suitable configuration. For example, the HVAC system 104 may include additional components or may omit one or more components shown in FIG. 6.

[0060] The HVAC system 104 may comprise a working-fluid conduit subsystem 602 for moving a working fluid, or refrigerant, through a cooling cycle. The working fluid may be any acceptable working fluid, or refrigerant, including, but not limited to, fluorocarbons (e.g., chlorofluorocarbons), ammonia, non-halogenated hydrocarbons (e.g., propane), hydrofluorocarbons (e.g., R-410A), or any other suitable type of refrigerant.

[0061] The HVAC system 104 comprises one or more condensing units 603. In one embodiment, the condensing unit 603 comprises a compressor 604, a condenser 606, and a fan 608. The compressor 604 is coupled to the working-fluid conduit subsystem 602 that compresses the working fluid. The condensing unit 603 may be configured with a single-stage or multi-stage compressor 604. A single-stage compressor 604 is configured to operate at a constant speed to increase the pressure of the working fluid to keep the working fluid moving along the working-fluid conduit subsystem 602. A multi-stage compressor 604 comprises multiple compressors configured to operate at a constant speed to increase the pressure of the working fluid to keep the working fluid moving along the working-fluid conduit subsystem 602. In this configuration, one or more compressors may be turned on or off to adjust the cooling capacity of the HVAC system 104. In some embodiments, a compressor 604 may be configured to operate at multiple speeds or as a variable speed compressor. For example, the compressor 604 may be configured to operate at multiple predetermined speeds.

[0062] In one embodiment, the condensing unit 603 (e.g., the compressor 604) is in signal communication with a controller 102 using a wired or wireless connection. The controller 102 is configured to provide commands or signals to control the operation of the compressor 604. For example, the controller 102 is configured to send signals to turn on or off one or more compressors 604 when the condensing unit 603 comprises a multi-stage compressor 604. In this configuration, the controller 102 may operate the multi-stage compressors 604 in a first mode where all the compressors 604 are on and a second mode where at least one of the compressors 604 is off. In some examples, the controller 102 may be configured to control the speed of the compressor 604.

[0063] The condenser 606 is configured to assist with moving the working fluid through the working-fluid conduit subsystem 602. The condenser 606 is located downstream of the compressor 604 for rejecting heat. The fan 608 is configured to move air 609 across the condenser 606. For example, the fan 608 may be configured to blow outside air through the heat exchanger to help cool the working fluid. The compressed, cooled working fluid flows downstream from the condenser 606 to an expansion device 610, or metering device.

[0064] The expansion device 610 is configured to remove pressure from the working fluid. The expansion device 610 is coupled to the working-fluid conduit subsystem 602 downstream of the condenser 606. The expansion device 610 is strongly associated with a cooling unit 612 (e.g., an evaporator coil). The expansion device 610 is coupled to the working-fluid conduit subsystem 602 downstream of the condenser 606 for removing pressure from the working fluid. In this way, the working fluid is delivered to the cooling unit 612 and receives heat from airflow 614 to produce a treated airflow 616 that is delivered by a duct subsystem 618 to the desired space, for example a room in the building.

[0065] A portion of the HVAC system 104 is configured to move air across the cooling unit 612 and out of the duct sub-system 618. Return air 620, which may be air returning from the building, fresh air from outside, or some combination, is pulled into a return duct 622. A suction side of a variable-speed blower 624 pulls the return air 620. The variable-speed blower 624 discharges airflow 614 into a duct 626 from where the airflow 614 crosses the cooling unit 612 or heating elements (not shown) to produce the treated airflow 616.

[0066] Examples of a variable-speed blower 624 include, but are not limited to, belt-drive blowers controlled by inverters, direct-drive blowers with electronically commutated motors (ECM), or any other suitable types of blowers. Conventional variable-speed blower 624 are typically configured to operate at multiple predetermined fan speeds. In contrast, the controller 102 is configured to operate the variable-speed blower 624 to operate at a fan speed that linearly correlates with temperature. In this configuration, the fan speed of the variable-speed blower 624 may vary dynamically based on a corresponding temperature value instead of relying on using predetermined fan speeds. In other words, the variable-speed blower 624 may be configured to dynamically adjust its fan speed over a range of fan speeds rather than using a set of predetermined fan speeds. This feature also allows the controller 102 to gradually transition the speed of the variable-speed blower 624 between different operating speeds. This contrasts with conventional configurations where a variable-speed blower 624 is abruptly switched between different predetermined fan speeds. The variable-speed blower 624 is in signal communication with the controller 102 using any suitable type of wired or wireless connection 627. The controller 102 is configured to provide commands or signals to the variable-speed blower 624 to control the operation of the variable-speed blower 624. For example, the controller 102 is configured to send signals to the variable-speed blower 624 to control the fan speed of the variable-speed blower 624. In some embodiments, the controller 102 may be configured to send other commands or signals to the variable-speed blower 624 to control any other functionality of the variable-speed blower 624.

[0067] The HVAC system 104 comprises one or more sensors 640 in signal communication with the controller 102. The sensors 640 may comprise any suitable type of sensor for measuring air temperature. The sensors 640 may be positioned anywhere within a conditioned space (e.g., a room or building) and / or the HVAC system 104. For example, the HVAC system 104 may comprise a sensor 640 positioned and configured to measure an outdoor air temperature. As another example, the HVAC system 104 may comprise a sensor 640 positioned and configured to measure a supply or treated air temperature and / or a return air temperature. In other examples, the HVAC system 104 may comprise sensors 640 positioned and configured to measure any other suitable type of air temperature.

[0068] The HVAC system 104 comprises one or more thermostats 106, for example located within a conditioned space (e.g., a room or building). A thermostat 106 may be a single-stage thermostat, a multi-stage thermostat, or any suitable type of thermostat as would be appreciated by one of ordinary skill in the art. The thermostat 106 is configured to allow a user to input a desired temperature or temperature set point for a designated space 122 or zone such as the room. The controller 102 may use information from the thermostat 106 such as the temperature set point for controlling the compressor 604 and the variable-speed blower 624. The thermostat 106 is in signal communication with the controller 102 using any suitable type of wired or wireless communications.Scope of the Disclosure

[0069] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

[0070] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

[0071] To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112 (f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.

Examples

example process

[0046]FIGS. 4A and 4B are a flowchart of an embodiment of a dynamic prediction process 400 for an HVAC system 104, in accordance with one or more embodiments. Modifications, additions, or omissions may be made to the process 400. The process 400 may comprise more, fewer, or other operations than those shown in FIGS. 4A and 4B. For example, operations may be performed in parallel or in any suitable order. While at times discussed as the controller 102, the HVAC system 104, the thermostat 106, one or more devices 108, and / or components of any of thereof performing operations described in operations 402-458 in the process 400, any suitable system or components of the system 100 may perform one or more operations of the process 400. For example, one or more operations of the process 400 may be implemented, at least in part, in the form of instructions, stored on non-transitory, tangible, machine-readable media (e.g., a non-transitory computer-readable medium such as memory 504 of FIG. 5...

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 763,863, filed Feb. 26, 2025, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to thermostat control for a heating, ventilation, and air conditioning (HVAC) system, and more specifically to a thermostat performing predictive demand termination for temperature overshoot control.BACKGROUND

[0003] A heating, ventilation, and air conditioning (HVAC) system may be utilized generally to regulate temperature within an enclosed space. Specifically, air is cooled via heat transfer with refrigerant flowing through the HVAC system and returned to the enclosed space as conditioned air. While some enclosed spaces may include multiple HVAC systems, temperatures may nevertheless vary across enclosed spaces depending on the physical dimensions and the architecture of the enclosed spaces. Further, temperatures may vary across enclosed spaces depending on a thermostat's ability to accurately set temperature set points within the enclosed spaces.SUMMARY

[0004] In one or more embodiments, a system and method described herein are configured to perform predictive demand termination for temperature overshoot control in a thermostat. In particular, the system may be configured to account for changes in the load of a heating, ventilation, and air conditioning (HVAC) system. The load may be changed by modifying a set point temperature in a space (e.g., an enclosed space). Herein, the system is configured to inhibit and / or eliminate temperature overshoots for an HVAC demand cycle under light system loads. The system may be configured to dynamically adjust an expected duration of demand cycles in the HVAC system to inhibit and / or eliminate overshoots when controlling a temperature of the space. At the moment of controlling the HVAC system to change the temperature in the space, a thermostat may be configured to compensate for any changes in HVAC loads. Herein, the system is configured to accurately set an actual temperature in a space without being affected by changes in the HVAC loads.

[0005] In some embodiments, the system provides technical solutions for technical problems. In this regard, the system is configured to accurately set a temperature in a space while the HVAC system transitions from one state to another state. The states may comprise operations in which resource consumption at the thermostat is modified. For example, an “idle” state for the thermostat may be a period of time in which the thermostat is in low-power consumption as a temperature inside the space is allowed to fluctuate freely and / or within a range. In another example, an “active” state for the thermostat may be a period of time in which the thermostat is required to consume large amounts of its memory resources and processing resources to control an HVAC system to modify the temperature and / or humidity in a space.

[0006] In conventional systems, as the HVAC system transitions between states, the temperature in the space may be incorrectly modified due to improper accounting of an HVAC load. Incorrect sampling coupled with incorrect accounting of the HVAC loads leads to incorrect temperature and / or humidity regulation in the space. The lack of reliable temperature and / or humidity regulation may cause irreparable losses to users, infrastructure, and / or operations in the space. For example, an inaccurate temperature control in a space comprising a datacenter may cause servers to overheat. Overheating servers may lead to various issues including data loss, system malfunctions, performance degradation, and potential damage to physical components of the server.

[0007] In one or more embodiments, contrary to conventional systems, the system disclosed herein is configured to monitor error functions associated with a difference between a sensed temperature and a set point temperature over a demand cycle. As the demand cycle concludes, the system may be configured to determine an overshoot of the demand cycle and analyze the overshoot to predict a future demand cycle. In this regard, the system may be configured to control future demand cycles to account for information associated with previously sampled overshoots.

[0008] In one or more embodiments, the systems may comprise an apparatus, such as an HVAC control device. Further, the device may be a data exchange system, which comprises the apparatus. In addition, the device may be configured to perform operations as part of a process performed by the apparatus. As a non-limiting example, the apparatus may comprise a network interface configured to communicate with one or more devices, a memory, and a processor communicatively coupled to one another. The processor may be configured to trigger a demand cycle in which an HVAC system is configured to match a sensed temperature in a space to a set point temperature and collect event data for the demand cycle from one or more devices. The event data may comprise a timestamp indicating a start time of the demand cycle, a set point temperature value for the HVAC system, and a sensed temperature value of the space.

[0009] Further, the processor may be configured to electronically calculate, over the demand cycle, a temperature error between the set point temperature and the sensed temperature, electronically extract a rate of change value of the temperature error over a first portion of the demand cycle, determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error at an expected end time of the demand cycle; and monitor the temperature error over a second portion of the demand cycle.

[0010] In conjunction with monitoring the temperature error over the second portion of the demand cycle, the processor may be configured to determine whether the temperature error matches the predicted temperature error. Further, the processor may be configured to associate a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle in response to determining that the temperature error matches the predicted temperature error and monitor the rate of change of the temperature error over a period of time that is subsequent to the demand cycle.

[0011] In conjunction with monitoring the rate of change of the temperature error over the period of time, the processor may be configured to determine whether the rate of change of the temperature error is equal to a limit value (e.g., preset value, such as zero). Further, the processor may be configured to associate an additional point in time where the rate of change of the temperature error is determined to be equal to the limit value with a corrected end time of the demand cycle in response to determining that the rate of change of the temperature error is equal to the limit value, assign, based on the start time and the corrected end time, an expected time duration for an additional demand cycle, and trigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature over the expected time duration.

[0012] Certain embodiments of the present disclosure may include some, all, or none of these advantages. These advantages and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0014] FIG. 1 is a schematic diagram of heating, ventilation, and air conditioning (HVAC) control system in accordance with one or more embodiments;

[0015] FIGS. 2A and 2B illustrate dynamic control of demand cycles as performed by the system of FIG. 1 in accordance with one or more embodiments;

[0016] FIG. 3 is an operational flow comprising predictive demand termination for temperature overshoot control performed by the system of FIG. 1 in accordance with one or more embodiments;

[0017] FIGS. 4A and 4B are a flowchart of an embodiment of a thermostat predictive demand termination method performed by the system of FIG. 1 in accordance with one or more embodiments;

[0018] FIG. 5 is a schematic diagram of an embodiment of a device configured to control an HVAC system in accordance with one or more embodiments; and

[0019] FIG. 6 is a schematic diagram of an embodiment of an HVAC system in accordance with one or more embodiments.DETAILED DESCRIPTION

[0020] As described above, this disclosure provides various systems and methods to perform predictive demand termination for temperature overshoot control.Information System Overview

[0021] FIG. 1 is a schematic diagram of heating, ventilation, and air conditioning (HVAC) control system 100 that is configured to perform multi-state predictive temperature compensation operations. In one embodiment, the HVAC control system 100 comprises a controller 102, an HVAC system 104, a thermostat 106, and devices 108 that are in signal communication with each other in a network 124.

[0022] The network 124 may be any suitable type of wireless and / or wired network including, but not limited to, all or a portion of the Internet, an Intranet, a private network, a public network, a peer-to-peer network, the public switched telephone network, a cellular network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), and a satellite network. The network 124 may be configured to support any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.

[0023] The HVAC system 104 is generally configured to control the temperature of a space 122. Examples of a space 122 include, but are not limited to, a room, a home, an office, or a building. The HVAC system 104 may comprise a thermostat 106, compressors, blowers, evaporators, condensers, and / or any other suitable type of hardware for controlling the temperature of the space 122 as would be appreciated by one of ordinary skill in the art. An example of an HVAC system 104 configuration and its components is described below in FIG. 6. The HVAC system 104 comprises one or more thermostats 106 located within the space 122. A thermostat 106 may be a single-stage thermostat, a multi-stage thermostat, or any suitable type of thermostat as would be appreciated by one of ordinary skill in the art. The thermostat 106 is configured to allow a user to select a desired temperature or set point temperature for the space 122. The controller 102 may use information from the thermostat 106 such as the set point temperature for controlling a compressor and / or a blower. In one embodiment, the thermostat 106 and the controller 102 are integrated into a single device. In another embodiment, the thermostat 106 may be a device that is external from the controller 102. In this example, the thermostat 106 is in signal communication with the controller 102 using any suitable type of wired or wireless communications.

[0024] The controller 102 is further configured to perform multi-state predictive temperature compensation. In some embodiments, contrary to conventional systems, the controller 102 is configured to accurately compensate for internal heat rise in the thermostat 106, where a single compensation value is not sufficient to cover multiple states. For example, the controller 102 may be configured to evaluate multiple collected temperature values from inside the thermostat 106 in accordance with specific state conditions to obtain one or more compensation values. The controller 102 is configured to provide a sensed temperature value in a space using an overall compensation value. The overall compensation value is electronically calculated by dynamically weighting different compensation values at different rates. The controller 102 may use the sensed temperature to trigger operations in an HVAC system to adjust a temperature more precisely in the space.

[0025] The controller 102 may be configured to control the operation of the HVAC system 104 using artificial intelligence (AI). In one embodiment, the controller 102 is configured to collect event data 114 from one or more devices 108 to generate an artificial intelligence model 112 for predicting an occupancy schedule and / or a set point temperature schedule for the space 122. Examples of devices 108 include, but are not limited to, computers, mobile devices (e.g., smart phones or tablets), user devices, Internet-of-things (IoT) devices, home automation devices, AI devices, motion sensors, proximity sensors, or any other suitable type of device. An event is an action that is taken by a user that provides information to the controller 102 about a user's behavior or preferences. The event data 114 may comprise a timestamp 116 indicating a time when an event occurred, an occupancy status 118 (e.g., a present status or an away status) for a user, a set point temperature 120, a source identifier that identifies a data source (e.g., a device identifier), a user identifier, a space identifier, or any other suitable type of information.Sample Embodiments

[0026] FIGS. 2A and 2B illustrate a sample 200a and a sample 200b, respectively, in which the system 100 of FIG. 1 is configured to perform dynamic prediction of demand cycles for temperature overshoot control in a thermostat 106, in accordance with one or more embodiments. The sample 200a and the sample 200b may be embodiments showing a load change in the HVAC system 104 over time. The sample 200a and the sample 200b may be generated after performing one or more operations by the controller 102, the HVAC system 104, the thermostat 106, and / or one or more devices 108. In FIGS. 2A and 2B, demand cycles are shown in comparison with a load consumption over time. The samples 200a-200b show the demand cycle as defined by values of temperature error Terror and time. The temperature error Terror may be a difference between a set point temperature and a sensed temperature. The sensed temperature may be referred to as HSP for heating sensed temperature Tsensed and CSP for cooling sensed temperature Tsensed.

[0027] In FIG. 2A, the sample 200a shows a demand curve changing vertically with reference to an axis 202 and changing horizontally with reference to an axis 204. The sample 200a shows a demand cycle 210 in which the HVAC system 104 is configured to account for a new load value. The demand cycle 210 may comprise a portion 212 and a portion 214. The portion 212 and the portion 214 may correspond to specific behavior of the demand curve. For example, the portion 212 may correspond to a prior portion of the demand cycle 210 and the portion 214 may correspond to an active portion of the demand cycle 210. The HVAC system 104 may be active throughout the demand cycle 210 and possibly after. Herein, the demand cycle 210 may be representative that the thermostat 106 is actively (e.g., currently) asking the HVAC system 104 for output. For example, individual controllers in the HVAC system 104 (e.g., in an indoor unit) may be kept running after the thermostat 106 ends demand (e.g., to exhaust a heat built up in a heat exchanger or coil). A reason for a continued increase in temperature error after the start of a demand cycle 210 may be that the HVAC system 104 has some inertia because the HVAC system 104 may take time to effect change in temperature, and there may be effects of duct temperature on a conditioned space. In the example of FIG. 2A, the demand cycle 210 changes from a point in time 220 (e.g., a time point) and a point in time 222. The demand cycle 210 may last from the point in time 220 where the temperature error Terror is less than an ON-demand temperature to the point in time 222 where the temperature error Terror is greater than an OFF-demand temperature. A difference between the point in time 220 and the point in time 222 may be a period of time. At a point in time 224, the demand curve may change from a rising behavior to a falling behavior as exemplified by point 226.

[0028] In some embodiments, a difference in time from a point in time 220 to the point in time 224 may last a duration 230. The duration 230 may comprise a duration 232 and a duration 234. The duration 232 may comprise a fall in the demand curve after the demand cycle is started. The duration 234 may comprise a raise in the demand curve after the demand cycle reaches a lower point (in comparison to the rest of the demand curve) and / or the lowest point in the demand curve and until the demand curve reaches a higher point (in comparison to the rest of the demand curve) and / or the highest point in the demand curve.

[0029] In one or more embodiments, a difference in the temperature error Terror from an error value where the demand cycle ends to the highest point in the demand curve is considered an overshoot 240 of the demand cycle. In some embodiments, the overshoot 240 shows a response of the HVAC system 104 where a sudden input change (e.g., in the load change of the HVAC system 104) exceeds an intended output level. In FIG. 2A, the demand cycle 210 does not meet the duration 230.

[0030] In FIG. 2B, the sample 200b shows a demand curve changing vertically with reference to an axis 252 and changing horizontally with reference to an axis 254. The sample 200b shows a demand cycle 260 in which the HVAC system 104 is configured to account for a new load value. The demand cycle 260 may comprise a portion 262 and a portion 264. The portion 262 and the portion 264 may correspond to specific behavior of the demand curve. For example, the portion 262 may correspond to a prior portion of the demand cycle 260 and the portion 264 may correspond to an active portion of the demand cycle 260. In the example of FIG. 2B, the demand cycle 260 changes from a point in time 270 (e.g., a time point) and a point in time 272. The demand cycle 260 may last from the point in time 270 where the temperature error Terror is less than an ON-demand temperature to the point in time 272 where the temperature error Terror is greater than an OFF-demand temperature. A difference between the point in time 270 and the point in time 272 may be a period of time. At a point in time 274, the demand curve may change from a rising behavior to a falling behavior as exemplified by point 276.

[0031] In some embodiments, a difference in time from a point in time 270 to the point in time 272 may last a duration 280. The duration 280 may comprise a duration 282 and a duration 284. The duration 282 may comprise a fall in the demand curve after the demand cycle is started. The duration 284 may comprise a raise in the demand curve after the demand cycle reaches a lower point (in comparison to the rest of the demand curve) and / or the lowest point in the demand curve and until the demand curve reaches a higher point (in comparison to the rest of the demand curve) and / or the highest point in the demand curve.

[0032] In one or more embodiments, a difference in the temperature error Terror from an error value where the demand cycle ends to the highest point in the demand curve is considered an overshoot 290 of the demand cycle. In some embodiments, the overshoot 290 shows a response of the HVAC system 104 where a sudden input change (e.g., in the load change of the HVAC system 104) exceeds an intended output level. In FIG. 2B, the demand cycle 260 meets most of the duration 280 by being active.

[0033] In one or more embodiments, the sample 200a may be a first demand curve in which an HVAC system 104 runs a demand cycle 210 for a first load. During the entirety of the sample 200a, An HVAC control device may be configured to monitor and analyze changes in the demand curve, analyze information associated with one or more points in the demand curve, and use results from the analyses to generate one or more commands to control future demand cycles. For example, the analyses of the demand cycle 210 in the sample 200a may be used to dynamically control the demand cycle 260 in the sample 200b. Herein, the sample 200a and the sample 200b may be subsequent load control samples in which the HVAC system 104 dynamically compensates load control from the sample 200a to the sample 200b.

[0034] In one or more embodiments, when controlling temperature in a conditioned space (e.g., an embodiment of the space 122) using staged control operations, the controller 102 and / or the thermostat 106 may be configured to calculate a temperature error Terror between a temperature setpoint Tsetpoint and a sensed temperature Tsensed. The temperature error Terror may be represented in the following embodiment:Te⁢r⁢r⁢o⁢r=Ts⁢e⁢n⁢s⁢e⁢d-Ts⁢etpoint

[0035] The controller 102 and / or the thermostat 106 may be configured to monitor the temperature error as a reference parameter to control load demands for heating and cooling in the HVAC system 104. The controller 102 and / or the thermostat 106 may call for a demand cycle when the temperature error Terror drops below a threshold relative to the set point temperature and stop the demand cycle when the temperature error Terror rises above another threshold above the set point temperature. The HVAC system 104 may comprise a blower-off delay to extract additional energy from the demand cycle. If system capacity is large compared to a load on the HVAC system 104, when the demand is ended, a temperature may keep rising above a set point temperature. The additional raise above the set point temperature may create an overshoot (e.g., the overshoot 240 in FIG. 2A and the overshoot 290 in FIG. 2B) relative to the targeted temperature in the conditioned space. In some instances, larger overshoots may lead to an experienced inaccuracy of the control of the temperature to the selected set point temperature by controller 102 and / or the thermostat 106.

[0036] In one or more embodiments, the HVAC control device may be configured to reduce, inhibit, and / or eliminate the overshoot. The HVAC control device may be configured to monitor a slope of the temperature error Terror during an active portion of the demand cycle, use the monitored slope to electronically calculate a predicted error for a set period tprediction into the future, and ending the demand cycle when an upper threshold is met based on a predicted error at a predicted ending time. Further, the HVAC control device may be configured to monitor the slope of the temperature error Terror after completion of the demand cycle to determine an amount of time in which the temperature keeps rising and capturing the amount of time as additional time configured to inform a new value for tprediction in a subsequent demand cycle.

[0037] In some embodiments, the HVAC control device creates an adaptive loop where changes in the demand cycle control the temperature error Terror positively or negatively. A change in the temperature error Terror may represent additional heating / cooling after an end of a demand cycle. Herein, the change is captured in an updated value of the set period tprediction and accounted for in a subsequent (e.g., next) demand cycle, limiting, inhibiting, and / or removing the overshoot. Limiting, inhibiting, and / or removing the amount of positive or negative adjustment of the set period tprediction per cycle may be configured to control min / max set time tprediction, and minimum actual temperature error Terror to let the predicted temperature error Terror take effect.Operational Flow

[0038] FIG. 3 shows an operational flow 300 in which the system 100 of FIG. 1 is configured to perform dynamic predictions of demand cycles for temperature overshoot control in a thermostat 106, in accordance with one or more embodiments. The operational flow 300 may be performed by the controller 102, the HVAC system 104, the thermostat 106, and / or one or more devices 108. In FIG. 3, the operational flow 300 comprises multiple operations performed by one or more elements, electronic components, and / or devices. In FIG. 3, the one or more elements, electronic components, and / or devices may comprise a slope calculator 302, a temperature error calculator 304, a temperature error predictor 306, and a demand control 308. The one or more elements, electronic components, and / or devices may be configured to receive inputs 310-320 and generate and / or create outputs 342-350.

[0039] In one or more embodiments, the inputs 310-316 may comprise temperature samples at different points in time. In some embodiments, the input 316 may be a first temperature value Tn-0, the input 314 may be a second temperature value Tn-1 that is prior to the first temperature value Tn-0, the input 312 may be a third temperature value Tn-2 that is prior to the second temperature value Tn-1, and the input 310 may be a fourth temperature value Tn-3 that is prior to the third temperature value Tn-2. The first temperature value Tn-0 may be a current temperature value. The inputs 310-316 may be provided to the slope calculator 302, which may sample the temperature values over a time duration. In some embodiments, the slope calculator 302 may be configured to generate the output 342 comprising a slope value. The slope value may be a rate of change of the temperature collected in the inputs 310-316 over a period of time. The measurement units associated with the rate of change may be a temperature measurement value over a time measurement value. For example, the rate of change may be degrees in Fahrenheit (F) or Celsius (C) over time in seconds(s).

[0040] In one or more embodiments, the input 318 and the input 320 may comprise temperature samples at different points in time. In some embodiments, the input 318 may be the first temperature value Tn-0 and the input 320 may be a set point temperature value Tsp. The input 318 and the input 320 may be provided to the temperature error calculator 304, which may electronically calculate a difference between the sampled temperature value Tn-0 and the set point temperature value Tsp. The first temperature value Tn-0 may be a current temperature value. In some embodiments, the temperature error calculator 304 may be configured to generate the output 344 comprising the temperature error Terror (or Terr). The measurement unit for the temperature error Terror may be a temperature measurement value. For example, the temperature measurement value may be degrees in Fahrenheit (° F.) or Celsius (° C.).

[0041] In one or more embodiments, the temperature error predictor 306 may be configured to receive multiple inputs 332 and generate an output 346 and an output 348. The temperature error predictor 306 may be configured to receive the output 342 and the output 344 as inputs. In some embodiments, the temperature error predictor 306 may be configured to predict a future error temperature value at a given time. In some embodiments, the temperature error predictor 306 may be configured to generate the output 346 comprising a prediction set time tprediction. The measurement unit of the set time may be a time measurement value. For example, the time measurement value may be in seconds(s). Further, the temperature error predictor 306 may be configured to generate the output 348 comprising the temperature error Terror and a predicted temperature error Terr-predicted′ which is an expected temperature error the temperature error Terror at the end of the prediction set time tprediction. The measurement unit of the predicted temperature error Terr-predicted may be a temperature measurement value. For example, the temperature measurement value may be degrees in Fahrenheit (F) or Celsius (° C.).

[0042] In some embodiments, demand control 308 may be configured to generate a demand output 350 that may be applied to temperature error predictor 306 to refine the temperature error and predicted temperature error of output 348. The demand control 308 may be configured to generate output 350 based at least in part upon the output 348. The demand control 308 may be configured to generate the output 350 comprising a demand value, which is signaling configured to cause a change in the temperature of the space 122. The demand value may be provided to the HVAC system 104, which is configured to modify flow of air at a magnitude proportionate to the demand value. The measurement unit of the demand value may be a temperature value. For example, the temperature value may be degrees in Fahrenheit (F) or Celsius (° C.).

[0043] In one or more embodiments, the inputs 332 may comprise one or more initial values in the HVAC system 104. These initial values may be a time set prediction default time tprediction-default, a maximum time set prediction time boundary tprediction-max, a minimum time set prediction time boundary tprediction-min, and a time set prediction step tprediction-step, which are used as a reference from which to calculate the prediction set time tprediction. The time set prediction default time tprediction-default may be a default time used when no prior information is available to modify the prediction set time tprediction. The time set prediction default time tprediction-default may be representative of a duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating an average duration for a specific load. The maximum time set prediction time boundary tprediction-max may be a limit to which the value of the prediction set time tprediction may be adjusted. The maximum time set prediction time boundary tprediction-max may be a maximum duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating a maximum expected duration for a specific load. The minimum time set prediction time boundary tprediction-min may be a limit to which the value of the prediction set time tprediction may be adjusted (e.g., zero). The minimum time set prediction time boundary tprediction-min may be a minimum duration of a demand cycle at a specific load determined by sampling multiple demand cycles and calculating a minimum expected duration for a specific load. The time set prediction step tprediction-step may be a default step increase of a duration for the prediction set time tprediction. The measurement units of the a time set prediction default time tprediction-default, the maximum time set prediction time boundary tprediction-max, the minimum time set prediction time boundary tprediction-min, and the time set prediction step tprediction-step may be time measurement values. For example, the time measurement value may be in seconds(s). The rate of change in the demand cycle may be contained at a specific limit slope value limit slope. The specific limit slope value limitslope may be a value of a calculated slope where at which the temperature error Terror is no longer considered rising after a termination of the demand. In this regard, a limit used to determine an adjustment of prediction set time tprediction after demand is completed. The measurement units associated with the specific limit slope value limitslope may be a temperature measurement value over a time measurement value. For example, the rate of change may be degrees in Fahrenheit (° F.) or Celsius (C) over time in seconds(s).

[0044] In one or more embodiments, during an active portion of a demand cycle, the HVAC control device may be configured to monitor a calculated slope (e.g., an absolute value), electronically calculate the temperature error Terror relative to the setpoint temperature, and electronically calculate the predicted temperature error Terr-predicted at the end of the prediction set time tprediction for a future demand cycle based on rates of change in demand curves. If the predicted temperature error Terr-predicted is less than a predetermined threshold, the demand cycle may be ended. If the predicted temperature error Terr-predicted is greater than or equal to a predetermined threshold, the demand cycle may be ended. Herein, the temperature error Terror may be used for staging and as boundary for shut off. Further, the temperature error Terror and predicted temperature error Terr-predicted may become positive when the HVAC system 104 has met a set point temperature and demand ends when reaching a set positive limit.

[0045] In one or more embodiments, as the demand cycle transitions from the active portion of the demand cycle to a no demand portion, the HVAC control device may be configured to capture a time of demand state change and monitor an electronic calculated slope (e.g., an absolute value). Herein, as long as the rate of change value of the temperature error Terror over time during the demand cycle is greater than the specific limit slope value limitslope (e.g., slope≥limitslope), the HVAC control device may continue monitoring the rate of change value of the temperature error Terror over time. In some embodiments, when the rate of change value of the temperature error Terror over time during the demand cycle is less than or equal to the specific limit slope value limitslope (e.g., slope≤limitslope), latch the prediction set time tprediction as a delta to time of demand state change and limit checks against the minimum time set prediction time boundary tprediction-min and the maximum time set prediction time boundary tprediction-max for subsequent demand cycles.Example Process

[0046] FIGS. 4A and 4B are a flowchart of an embodiment of a dynamic prediction process 400 for an HVAC system 104, in accordance with one or more embodiments. Modifications, additions, or omissions may be made to the process 400. The process 400 may comprise more, fewer, or other operations than those shown in FIGS. 4A and 4B. For example, operations may be performed in parallel or in any suitable order. While at times discussed as the controller 102, the HVAC system 104, the thermostat 106, one or more devices 108, and / or components of any of thereof performing operations described in operations 402-458 in the process 400, any suitable system or components of the system 100 may perform one or more operations of the process 400. For example, one or more operations of the process 400 may be implemented, at least in part, in the form of instructions, stored on non-transitory, tangible, machine-readable media (e.g., a non-transitory computer-readable medium such as memory 504 of FIG. 5) that when run by one or more processors (e.g., the processor 502 of FIG. 5) may cause the one or more processors to perform operations described in operations 402-458.

[0047] The process 400 starts at operation 402, where an HVAC control device is configured to trigger a demand cycle in which an HVAC system 104 is configured to match a sensed temperature Tsensed in a space 122 to a set point temperature Tsetpoint. At operation 404, the HVAC control device is configured to collect event data 114 for the demand cycle from one or more devices 108. The event data 114 may comprise a timestamp 116 indicating a start time of the demand cycle, a set point temperature value for the HVAC system 104, and a sensed temperature value of the space 122. At operation 406, the HVAC control device is configured to electronically calculate, over the demand cycle, a temperature error Terror between the set point temperature Tsetpoint and the sensed temperature Tsensed. At operation 408, the HVAC control device is configured to electronically extract a rate of change value of the temperature error Terror over a first portion of the demand cycle. At operation 410, the HVAC control device is configured to determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error Terror-predicted at an expected end time of the demand cycle. At operation 412, the HVAC control device is configured to monitor the temperature error Terror over a second portion of the demand cycle.

[0048] At operation 420, the HVAC control device is configured to determine whether a temperature error Terror matches a previously predicted temperature error Terr-predicted for a current demand. In some embodiments, when a demand starts, a temperature error Terror along with the slope of the a temperature error Terror and the prediction set time tprediction is used to determine the predicted temperature error Terr-predicted. Herein, the predicted temperature error Terr-predicted may be used to determine when to end the demand. Once demand is ended, the slope of the temperature error Terror and time since demand ended is used to determine a modified prediction set time tprediction for a next cycle.

[0049] If the HVAC control device determines that the temperature error Terror does not match the predicted temperature error Terror-predicted (e.g., NO), the process 400 proceeds to operation 422. At operation 422, the HVAC control device is configured to determine that the temperature error Terror does not match the predicted temperature error Terror-predicted. If the HVAC control device determines that the temperature error Terror matches the predicted temperature error Terror-predicted (e.g., YES), the process 400 proceeds to operation 432. At operation 432, the HVAC control device is configured to determine that the temperature error Terror matches the predicted temperature error Terror-predicted. At operation 434, the HVAC control device is configured to associate a point in time where the temperature error Terror is determined to match the predicted temperature error Terror-predicted with an end time of the demand cycle. At operation 436, the HVAC control device is configured to monitor the rate of change of the temperature error Terror over a period of time that is subsequent to the demand cycle.

[0050] The process 400 continues at operation 440, where the HVAC control device is configured to determine whether a rate of change of the temperature error Terror over time is greater than or equal to a threshold value (e.g., the limit slope value limit slope). Herein, the threshold value may be equal to a limit value (e.g., preset value, such as zero). If the HVAC control device determines that the rate of change is not greater than or equal to the threshold value (e.g., NO), the process 400 proceeds to operation 442. At operation 442, the HVAC control device is configured to determine that the rate of change of the temperature error Terror does not meet the threshold value. If the HVAC control device determines that the rate of change is greater than or equal to the threshold value (e.g., YES), the process 400 proceeds to operation 452. At operation 452, the HVAC control device is configured to determine that the rate of change of the temperature error Terror meets the threshold value. At operation 454, the HVAC control device is configured to associate an additional point in time where the rate of change of the temperature error Terror is determined to be equal to match the threshold with a corrected end time of the demand cycle. At operation 456, the HVAC control device is configured to assign, based on the start time and the corrected end time, an expected time duration Tsetpoint for an additional demand cycle.

[0051] The process 400 may end at operation 458, where the HVAC control device is configured to trigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature Tsetpoint over the expected time duration Tsetpoint.

[0052] In one or more embodiments, the HVAC control device may be configured to dynamically inhibit and / or eliminate overshoots in demand cycles under light system loads. In some embodiments, a difference between demand overshoots of two demand curves may be a positive adjustment value. Further, difference between demand overshoots of two demand curves may be a negative adjustment value. The demand cycle may be triggered by an interaction between a user and an adjustment in a set point interface. The demand cycle may be triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by at least one of the one or more devices 108. The demand cycle may be triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by the HVAC system 104.Controller Hardware Configuration

[0053] FIG. 5 is an embodiment of a device (e.g., controller 102) configured to control an HVAC system 104. The controller 102 comprises a processor 502, a memory 504, and a network interface 506. The controller 102 may be configured as shown or in any other suitable configuration.

[0054] The processor 502 may comprises one or more processors operably coupled to the memory 504. The processor 502 may be any electronic circuitry including, but not limited to, state machines, one or more central processing unit (CPU) chips, logic units, cores (e.g., a multi-core processor), field-programmable gate array (FPGAs), application specific integrated circuits (ASICs), or digital signal processors (DSPs). The processor 502 may be a programmable logic device, a microcontroller, a microprocessor, or any suitable combination of the preceding. The processor 502 may be communicatively coupled to and in signal communication with the memory 504. The one or more processors may be configured to process data and may be implemented in hardware or software. For example, the processor 502 may be 8-bit, 16-bit, 32-bit, 64-bit or of any other suitable architecture. The processor 502 may include an arithmetic logic unit (ALU) for performing arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and executes them by directing the coordinated operations of the ALU, registers and other components.

[0055] The one or more processors may be configured to implement various instructions. For example, the one or more processors may be configured to execute instructions to implement an HVAC control engine 508. In this way, processor 502 may be a special purpose computer designed to implement the functions disclosed herein. In an embodiment, the HVAC control engine 508 may be implemented using logic units, FPGAs, ASICs, DSPs, or any other suitable hardware. The HVAC control engine 508 may be configured to operate as described in FIGS. 1-4B. For example, the HVAC control engine 508 may be configured to perform the operations of process 400 as described in FIGS. 4A and 4B.

[0056] The memory 504 may comprise one or more disks, tape drives, or solid-state drives, and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution. The memory 504 may be volatile or non-volatile and may comprise read-only memory (ROM), random-access memory (RAM), ternary content-addressable memory (TCAM), dynamic random-access memory (DRAM), and static random-access memory (SRAM).

[0057] The memory 504 may be operable to store HVAC control instructions 510, event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514, and / or any other data or instructions. The HVAC control instructions 510 may comprise any suitable set of instructions, logic, rules, or code operable to execute the HVAC control engine 508. The event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514 may be configured similar to the event data 114, occupancy history logs 512, predicted occupancy schedules 110, historical set point temperature information 514 described in FIGS. 1-4.

[0058] The network interface 506 may be configured to enable wired and / or wireless communications. The network interface 506 may be configured to communicate data between the controller 102 and other devices (e.g., HVAC system 104, thermostat 106, and devices 108), systems, or domain. For example, the network interface 506 may comprise a WIFI interface, a LAN interface, a WAN interface, a modem, a switch, or a router. The processor 502 may be configured to send and receive data using the network interface 506. The network interface 506 may be configured to use any suitable type of communication protocol as would be appreciated by one of ordinary skill in the art.HVAC System Configuration

[0059] FIG. 6 is a schematic diagram of an embodiment of an HVAC system 104. The HVAC system 104 may condition air for delivery to an interior space of a building. In some embodiments, the HVAC system 104 is a rooftop unit (RTU) that is positioned on the roof of a building and the conditioned air is delivered to the interior of the building. In other embodiments, portions of the system may be located within the building and a portion outside the building. The HVAC system 104 may also include heating elements that are not shown here for convenience and clarity. The HVAC system 104 may be configured as shown in FIG. 6 or in any other suitable configuration. For example, the HVAC system 104 may include additional components or may omit one or more components shown in FIG. 6.

[0060] The HVAC system 104 may comprise a working-fluid conduit subsystem 602 for moving a working fluid, or refrigerant, through a cooling cycle. The working fluid may be any acceptable working fluid, or refrigerant, including, but not limited to, fluorocarbons (e.g., chlorofluorocarbons), ammonia, non-halogenated hydrocarbons (e.g., propane), hydrofluorocarbons (e.g., R-410A), or any other suitable type of refrigerant.

[0061] The HVAC system 104 comprises one or more condensing units 603. In one embodiment, the condensing unit 603 comprises a compressor 604, a condenser 606, and a fan 608. The compressor 604 is coupled to the working-fluid conduit subsystem 602 that compresses the working fluid. The condensing unit 603 may be configured with a single-stage or multi-stage compressor 604. A single-stage compressor 604 is configured to operate at a constant speed to increase the pressure of the working fluid to keep the working fluid moving along the working-fluid conduit subsystem 602. A multi-stage compressor 604 comprises multiple compressors configured to operate at a constant speed to increase the pressure of the working fluid to keep the working fluid moving along the working-fluid conduit subsystem 602. In this configuration, one or more compressors may be turned on or off to adjust the cooling capacity of the HVAC system 104. In some embodiments, a compressor 604 may be configured to operate at multiple speeds or as a variable speed compressor. For example, the compressor 604 may be configured to operate at multiple predetermined speeds.

[0062] In one embodiment, the condensing unit 603 (e.g., the compressor 604) is in signal communication with a controller 102 using a wired or wireless connection. The controller 102 is configured to provide commands or signals to control the operation of the compressor 604. For example, the controller 102 is configured to send signals to turn on or off one or more compressors 604 when the condensing unit 603 comprises a multi-stage compressor 604. In this configuration, the controller 102 may operate the multi-stage compressors 604 in a first mode where all the compressors 604 are on and a second mode where at least one of the compressors 604 is off. In some examples, the controller 102 may be configured to control the speed of the compressor 604.

[0063] The condenser 606 is configured to assist with moving the working fluid through the working-fluid conduit subsystem 602. The condenser 606 is located downstream of the compressor 604 for rejecting heat. The fan 608 is configured to move air 609 across the condenser 606. For example, the fan 608 may be configured to blow outside air through the heat exchanger to help cool the working fluid. The compressed, cooled working fluid flows downstream from the condenser 606 to an expansion device 610, or metering device.

[0064] The expansion device 610 is configured to remove pressure from the working fluid. The expansion device 610 is coupled to the working-fluid conduit subsystem 602 downstream of the condenser 606. The expansion device 610 is strongly associated with a cooling unit 612 (e.g., an evaporator coil). The expansion device 610 is coupled to the working-fluid conduit subsystem 602 downstream of the condenser 606 for removing pressure from the working fluid. In this way, the working fluid is delivered to the cooling unit 612 and receives heat from airflow 614 to produce a treated airflow 616 that is delivered by a duct subsystem 618 to the desired space, for example a room in the building.

[0065] A portion of the HVAC system 104 is configured to move air across the cooling unit 612 and out of the duct sub-system 618. Return air 620, which may be air returning from the building, fresh air from outside, or some combination, is pulled into a return duct 622. A suction side of a variable-speed blower 624 pulls the return air 620. The variable-speed blower 624 discharges airflow 614 into a duct 626 from where the airflow 614 crosses the cooling unit 612 or heating elements (not shown) to produce the treated airflow 616.

[0066] Examples of a variable-speed blower 624 include, but are not limited to, belt-drive blowers controlled by inverters, direct-drive blowers with electronically commutated motors (ECM), or any other suitable types of blowers. Conventional variable-speed blower 624 are typically configured to operate at multiple predetermined fan speeds. In contrast, the controller 102 is configured to operate the variable-speed blower 624 to operate at a fan speed that linearly correlates with temperature. In this configuration, the fan speed of the variable-speed blower 624 may vary dynamically based on a corresponding temperature value instead of relying on using predetermined fan speeds. In other words, the variable-speed blower 624 may be configured to dynamically adjust its fan speed over a range of fan speeds rather than using a set of predetermined fan speeds. This feature also allows the controller 102 to gradually transition the speed of the variable-speed blower 624 between different operating speeds. This contrasts with conventional configurations where a variable-speed blower 624 is abruptly switched between different predetermined fan speeds. The variable-speed blower 624 is in signal communication with the controller 102 using any suitable type of wired or wireless connection 627. The controller 102 is configured to provide commands or signals to the variable-speed blower 624 to control the operation of the variable-speed blower 624. For example, the controller 102 is configured to send signals to the variable-speed blower 624 to control the fan speed of the variable-speed blower 624. In some embodiments, the controller 102 may be configured to send other commands or signals to the variable-speed blower 624 to control any other functionality of the variable-speed blower 624.

[0067] The HVAC system 104 comprises one or more sensors 640 in signal communication with the controller 102. The sensors 640 may comprise any suitable type of sensor for measuring air temperature. The sensors 640 may be positioned anywhere within a conditioned space (e.g., a room or building) and / or the HVAC system 104. For example, the HVAC system 104 may comprise a sensor 640 positioned and configured to measure an outdoor air temperature. As another example, the HVAC system 104 may comprise a sensor 640 positioned and configured to measure a supply or treated air temperature and / or a return air temperature. In other examples, the HVAC system 104 may comprise sensors 640 positioned and configured to measure any other suitable type of air temperature.

[0068] The HVAC system 104 comprises one or more thermostats 106, for example located within a conditioned space (e.g., a room or building). A thermostat 106 may be a single-stage thermostat, a multi-stage thermostat, or any suitable type of thermostat as would be appreciated by one of ordinary skill in the art. The thermostat 106 is configured to allow a user to input a desired temperature or temperature set point for a designated space 122 or zone such as the room. The controller 102 may use information from the thermostat 106 such as the temperature set point for controlling the compressor 604 and the variable-speed blower 624. The thermostat 106 is in signal communication with the controller 102 using any suitable type of wired or wireless communications.Scope of the Disclosure

[0069] While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

[0070] In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

[0071] To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112 (f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.

Examples

example process

[0046]FIGS. 4A and 4B are a flowchart of an embodiment of a dynamic prediction process 400 for an HVAC system 104, in accordance with one or more embodiments. Modifications, additions, or omissions may be made to the process 400. The process 400 may comprise more, fewer, or other operations than those shown in FIGS. 4A and 4B. For example, operations may be performed in parallel or in any suitable order. While at times discussed as the controller 102, the HVAC system 104, the thermostat 106, one or more devices 108, and / or components of any of thereof performing operations described in operations 402-458 in the process 400, any suitable system or components of the system 100 may perform one or more operations of the process 400. For example, one or more operations of the process 400 may be implemented, at least in part, in the form of instructions, stored on non-transitory, tangible, machine-readable media (e.g., a non-transitory computer-readable medium such as memory 504 of FIG. 5...

Claims

1. A heating, ventilation, and air conditioning (HVAC) control device, comprising:a network interface configured to communicate with one or more devices; anda processor operably coupled to the network interface, and configured to:trigger a demand cycle in which an HVAC system is configured to match a sensed temperature in a space to a set point temperature;collect event data for the demand cycle from the one or more devices, wherein the event data comprises:a timestamp indicating a start time of the demand cycle;a set point temperature value for the HVAC system; anda sensed temperature value of the space;electronically calculate, over the demand cycle, a temperature error between the set point temperature and the sensed temperature;electronically extract a rate of change value of the temperature error over a first portion of the demand cycle;determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error at an expected end time of the demand cycle;monitor the temperature error over a second portion of the demand cycle;in conjunction with monitoring the temperature error over the second portion of the demand cycle, determine whether the temperature error matches the predicted temperature error;in response to determining that the temperature error matches the predicted temperature error, associate a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle;monitor the rate of change of the temperature error over a period of time that is subsequent to the demand cycle;in conjunction with monitoring the rate of change of the temperature error over the period of time, determine whether the rate of change of the temperature error is equal to a limit value;in response to determining that the rate of change of the temperature error is equal to the limit value, associate an additional point in time where the rate of change of the temperature error is determined to be equal to the limit value with a corrected end time of the demand cycle;assign, based on the start time and the corrected end time, an expected time duration for an additional demand cycle; andtrigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature over the expected time duration.

2. The device of claim 1, wherein the processor is further configured to:collect additional event data for the additional demand cycle from the one or more devices, wherein the additional event data comprises:an additional timestamp indicating an additional start time of the additional demand cycle;an additional set point temperature value for the HVAC system; andan additional sensed temperature value of the space;electronically calculate, over the additional demand cycle, an additional temperature error between the additional set point temperature and the additional sensed temperature;electronically extract an additional rate of change value of the additional temperature error over a first portion of the additional demand cycle;determine, based on the additional rate of change value over the first portion of the additional demand cycle, an additional predicted temperature error at an additional expected end time of the additional demand cycle;monitor the additional temperature error over a second portion of the additional demand cycle;in conjunction with monitoring the additional temperature error over the second portion of the additional demand cycle, determine whether the additional temperature error matches the additional predicted temperature error;in response to determining that the additional temperature error matches the additional predicted temperature error, associate a second additional point in time where the additional temperature error is determined to match the additional predicted temperature error with an additional end time of the additional demand cycle;monitor the additional rate of change of the additional temperature error over an additional period of time that is subsequent to the additional demand cycle;in conjunction with monitoring the additional rate of change of the additional temperature error over the additional period of time, determine whether the additional rate of change of the additional temperature error is equal to the limit value;in response to determining that the additional rate of change of the additional temperature error is equal to the limit value, associate a third additional point in time where the additional rate of change of the temperature error is determined to be equal to the limit value with an additional corrected end time of the additional demand cycle,wherein:the demand cycle is associated with a demand overshoot equal to a difference between a temperature error value at the expected end time of the demand cycle and a temperature error value at the corrected end time;the additional demand cycle is associated with an additional demand overshoot equal to an additional difference between the temperature error value at the additional expected end time of the additional demand cycle and the temperature error value at the additional corrected end time; andthe demand overshoot is greater than the additional demand overshoot;assign, based on the additional start time and the additional corrected end time, an additional expected time duration for a second additional demand cycle; andtrigger the second additional demand cycle in which the HVAC system is configured to match a second additional sensed temperature in the space to a second additional set point temperature over the additional expected time duration.

3. The device of claim 2, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a positive adjustment value.

4. The device of claim 2, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a negative adjustment value.

5. The device of claim 1, wherein:the demand cycle is triggered by an interaction between a user and an adjustment in a set point interface.

6. The device of claim 1, wherein:the demand cycle is triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by at least one of the one or more devices.

7. The device of claim 1, wherein:the demand cycle is triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by the HVAC system.

8. A method, comprising:triggering a demand cycle in which an HVAC system is configured to match a sensed temperature in a space to a set point temperature;collecting event data for the demand cycle from one or more devices, wherein the event data comprises:a timestamp indicating a start time of the demand cycle;a set point temperature value for the HVAC system; anda sensed temperature value of the space;electronically calculating, over the demand cycle, a temperature error between the set point temperature and the sensed temperature;electronically extracting a rate of change value of the temperature error over a first portion of the demand cycle;determining, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error at an expected end time of the demand cycle;monitoring the temperature error over a second portion of the demand cycle;in conjunction with monitoring the temperature error over the second portion of the demand cycle, determining whether the temperature error matches the predicted temperature error;in response to determining that the temperature error matches the predicted temperature error, associating a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle;monitoring the rate of change of the temperature error over a period of time that is subsequent to the demand cycle;in conjunction with monitoring the rate of change of the temperature error over the period of time, determining whether the rate of change of the temperature error is equal to a limit value;in response to determining that the rate of change of the temperature error is equal to the limit value, associating an additional point in time where the rate of change of the temperature error is determined to be equal to the limit value with a corrected end time of the demand cycle;assigning, based on the start time and the corrected end time, an expected time duration for an additional demand cycle; andtriggering the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature over the expected time duration.

9. The method of claim 8, further comprising:collecting additional event data for the additional demand cycle from the one or more devices, wherein the additional event data comprises:an additional timestamp indicating an additional start time of the additional demand cycle;an additional set point temperature value for the HVAC system; andan additional sensed temperature value of the space;electronically calculating, over the additional demand cycle, an additional temperature error between the additional set point temperature and the additional sensed temperature;electronically extracting an additional rate of change value of the additional temperature error over a first portion of the additional demand cycle;determining, based on the additional rate of change value over the first portion of the additional demand cycle, an additional predicted temperature error at an additional expected end time of the additional demand cycle;monitoring the additional temperature error over a second portion of the additional demand cycle;in conjunction with monitoring the additional temperature error over the second portion of the additional demand cycle, determining whether the additional temperature error matches the additional predicted temperature error;in response to determining that the additional temperature error matches the additional predicted temperature error, associating a second additional point in time where the additional temperature error is determined to match the additional predicted temperature error with an additional end time of the additional demand cycle;monitoring the additional rate of change of the additional temperature error over an additional period of time that is subsequent to the additional demand cycle;in conjunction with monitoring the additional rate of change of the additional temperature error over the additional period of time, determining whether the additional rate of change of the additional temperature error is equal to the limit value;in response to determining that the additional rate of change of the additional temperature error is equal to the limit value, associating a third additional point in time where the additional rate of change of the temperature error is determined to be equal to the limit value with an additional corrected end time of the additional demand cycle,wherein:the demand cycle is associated with a demand overshoot equal to a difference between a temperature error value at the expected end time of the demand cycle and a temperature error value at the corrected end time;the additional demand cycle is associated with an additional demand overshoot equal to an additional difference between the temperature error value at the additional expected end time of the additional demand cycle and the temperature error value at the additional corrected end time; andthe demand overshoot is greater than the additional demand overshoot;assigning, based on the additional start time and the additional corrected end time, an additional expected time duration for a second additional demand cycle; andtriggering the second additional demand cycle in which the HVAC system is configured to match a second additional sensed temperature in the space to a second additional set point temperature over the additional expected time duration.

10. The method of claim 9, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a positive adjustment value.

11. The method of claim 9, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a negative adjustment value.

12. The method of claim 8, wherein:the demand cycle is triggered by an interaction between a user and an adjustment in a set point interface.

13. The method of claim 8, wherein:the demand cycle is triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by at least one of the one or more devices.

14. The method of claim 8, wherein:the demand cycle is triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by the HVAC system.

15. A non-transitory computer-readable medium storing instructions that when executed by a processor cause the processor to:trigger a demand cycle in which an HVAC system is configured to match a sensed temperature in a space to a set point temperature;collect event data for the demand cycle from one or more devices, wherein the event data comprises:a timestamp indicating a start time of the demand cycle;a set point temperature value for the HVAC system; anda sensed temperature value of the space;electronically calculate, over the demand cycle, a temperature error between the set point temperature and the sensed temperature;electronically extract a rate of change value of the temperature error over a first portion of the demand cycle;determine, based on the rate of change value over the first portion of the demand cycle, a predicted temperature error at an expected end time of the demand cycle;monitoring the temperature error over a second portion of the demand cycle;in conjunction with monitoring the temperature error over the second portion of the demand cycle, determine whether the temperature error matches the predicted temperature error;in response to determining that the temperature error matches the predicted temperature error, associate a point in time where the temperature error is determined to match the predicted temperature error with an end time of the demand cycle;monitor the rate of change of the temperature error over a period of time that is subsequent to the demand cycle;in conjunction with monitoring the rate of change of the temperature error over the period of time, determine whether the rate of change of the temperature error is equal to a limit value;in response to determining that the rate of change of the temperature error is equal to the limit value associate an additional point in time where the rate of change of the temperature error is determined to be equal to the limit value with a corrected end time of the demand cycle;assign, based on the start time and the corrected end time, an expected time duration for an additional demand cycle; andtrigger the additional demand cycle in which the HVAC system is configured to match an additional sensed temperature in the space to an additional set point temperature over the expected time duration.

16. The non-transitory computer-readable medium of claim 15, wherein the instructions further cause the processor to:collect additional event data for the additional demand cycle from the one or more devices, wherein the additional event data comprises:an additional timestamp indicating an additional start time of the additional demand cycle;an additional set point temperature value for the HVAC system; andan additional sensed temperature value of the space;electronically calculate, over the additional demand cycle, an additional temperature error between the additional set point temperature and the additional sensed temperature;electronically extract an additional rate of change value of the additional temperature error over a first portion of the additional demand cycle;determine, based on the additional rate of change value over the first portion of the additional demand cycle, an additional predicted temperature error at an additional expected end time of the additional demand cycle;monitor the additional temperature error over a second portion of the additional demand cycle;in conjunction with monitoring the additional temperature error over the second portion of the additional demand cycle, determine whether the additional temperature error matches the additional predicted temperature error;in response to determining that the additional temperature error matches the additional predicted temperature error, associate a second additional point in time where the additional temperature error is determined to match the additional predicted temperature error with an additional end time of the additional demand cycle;monitor the additional rate of change of the additional temperature error over an additional period of time that is subsequent to the additional demand cycle;in conjunction with monitoring the additional rate of change of the additional temperature error over the additional period of time, determine whether the additional rate of change of the additional temperature error is equal to the limit value;in response to determining that the additional rate of change of the additional temperature error is equal to the limit value, associate a third additional point in time where the additional rate of change of the temperature error is determined to be equal to the limit value with an additional corrected end time of the additional demand cycle,wherein:the demand cycle is associated with a demand overshoot equal to a difference between a temperature error value at the expected end time of the demand cycle and a temperature error value at the corrected end time;the additional demand cycle is associated with an additional demand overshoot equal to an additional difference between the temperature error value at the additional expected end time of the additional demand cycle and the temperature error value at the additional corrected end time; andthe demand overshoot is greater than the additional demand overshoot;assign, based on the additional start time and the additional corrected end time, an additional expected time duration for a second additional demand cycle; andtrigger the second additional demand cycle in which the HVAC system is configured to match a second additional sensed temperature in the space to a second additional set point temperature over the additional expected time duration.

17. The non-transitory computer-readable medium of claim 16, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a positive adjustment value.

18. The non-transitory computer-readable medium of claim 16, wherein:an additional difference between the demand overshoot and the additional demand overshoot is a negative adjustment value.

19. The non-transitory computer-readable medium of claim 15, wherein:the demand cycle is triggered by an interaction between a user and an adjustment in a set point interface.

20. The non-transitory computer-readable medium of claim 15, wherein:the demand cycle is triggered by a dynamically predicted temperature adjustment trigger generated by a prediction engine hosted by at least one of the one or more devices.

Images